Retractable posts

ABSTRACT

A retractable post assembly incorporates a fluid operated piston and cylinder unit having a pair of pistons located one at each end, one of which pistons controls means for raising or retracting the post, and the other of which controls the operation of a member, such as a swinging arm, movably mounted on the post, so that by feeding fluid into the cylinder the post can first be raised and the movable member then moved from an inoperative to an operative position.

United States Patent 1191 Ingram et a1.

[ Apr. 9, 1974 RETRACTABLE POSTS Inventors: David John Ingram,Barnhurst;

Keith James Mitchell, Higham near Rochester, both of England The GeneralElectric Company Ltd., London, England Filed: June 28, 1972 Appl. No.:267,094

Foreign Application Priority Data July 1, 1971 Great Assignee:

us. 01 212/64, 212/35 R, 214/13 Int. Cl. B66c 23/02, B66c 23/56, B631)27/10 Field of Search 212/57, 64, 30-35; 214/13-15; 104/114 ReferencesCited UNITED STATES PATENTS 11/1967 Stonely 214/13 6/1971 Ingram....-...104/114 2/1967 Goss 9/1969 212/58 Potain .f. 212/57 FOREIGN PATENTS ORAPPLICATIONS 113,393 3/1945 Sweden 212/64 53,727 8/1967 Poland 212/5738,104 6/1956 Poland 212/64 Primary ExaminerRichard E. AegerterAssistant ExaminerJames W. Miller Attorney, Agent, or Firm-Kirschstein,Kirschstein, Ottinger & Frank [57] ABSTRACT A retractable post assemblyincorporates a fluid operated piston and cylinder unit having a pair ofpistons located one at each end, one of which pistons controls means forraising or retracting the post, and the other of which controls theoperation of a member, such as a swinging arm, movably mounted on thepost, so that by feeding fluid into the cylinder the post can first beraised and the movable member then moved from an inoperative to anoperative position.

11 Claims, 7 Drawing Figures IWENIEDAPR 9 I974 SHEET 3 UF 4 Fig.3

Fig.4

. 1 RETRACTABLE POSTS This invention relates to retractable posts ormasts, and especially, though not exclusively, to such posts or masts,hereinafter referred to simply as posts, which are of the kind designedto carry an end of a cable emtween two stations.

Such a retractable post may, forexample, be

mounted on a ship, for carrying an end of a support post in its raisedposition. In such an application it is desirable to maintain the end ofthe support cable at a sufficient height during transfer to allow forthe sag'at the centre of the cable, which can in some cases besubstantial and may vary considerably where the loads are beingtransferred between two ships at sea, due to rolling and other movementof the ships, and to variations in the distance between them. Tofacilitate loading and unloading it has therefore been proposed tosecure the end of the cable to a carrier member whichcan be loweredrelative to the post, the member being raised to an operative positionduring an actual transfer operation; such a carrier member convenientlycomprises a swinging arm pivoted to the post about a nominallyhorizontal axis so tha the end of the arm to which the support cable isarranged to be attached can be pivoted downwards to a loading/unloadingposition, or raised to an operative position as may be required.

An object of the invention is to provide a retractable post suitable forsuch an application.

According to the invention a retractable post incorporates a fluidoperated piston and cylinder unit having a pair of pistons located oneat each end, one of which pistons controls means for raising orretracting the post and the other of which controls the operation of acarrier member movably mounted on the post.

The carrier member may comprise a swinging arm as previously described,means being provided for latching the arm in a lowered, inoperative,position substantially parallel to the post to permit the post to beretracted. With such an arrangement the control system is simplifiedsince with the arm latched in its inoperative position by the latchingmeans, which can be of any no kind the admission of the working fluidinto the cylinder results in the raising of the post, but has not effecton the arm, but once the post has been raised to its operative position,and the arm unlatched, further admisployed to support a load as thelatter is transferred besion of working fluid into an appropriate partof the cylinderwill result in the raising of the arm.

Means. are preferably provided for latching the post in itsraisedposition, so that when it is required to raise or lower the armthis. can be simply effected by control of the working fluid, the postbeing prevented fromretracting by the latching means, which can be ofany convenientkind. I

Conveniently the piston that controls the raising and lowering of thepost is located at the lower end of the cylinder,- and is in the form ofa ram carrying a pulley,

acable havingone end connected to the post assembly and the other endconnected to a support member, passing round the pulley to provide asupport for the assembly so that as the ram is extended the assembly is2 raised. The cable conveniently passes around a plurality of otherpulleys carried by the assembly in order to magnify the movment of theassembly for a given movement of the ram, thus enabling a relativelylarge movement of the assembly to be obtained for a relatively smallmovement of the ram.

The support is conveniently provided by a slewing ring through which thepost assembly extends to permit the whole assembly to be rotated about anormallyvertical axis.

Preferably the raising and lowering of i the post and the movement ofthe arm are controlled by a hydraulic system, the various parts of thesystem being carried by thepost so that the whole of the post assemblycan be removed or replaced as a complete unit for servicing if thisbecomes necessary.

Conveniently the post assembly is substantially comcable to retractableking posts designed for supporting an end of a cable in 'high line loadtransfer systems, it will be appreciated thatit may also be used toadvantage with retractable posts employed for other purposes.

One embodiment of the invention will now be described by way of examplewith reference to FIGS. 1 to 7 of the accompanying schematic drawings,in which:

FIG. 1 represents a sectional elevation of a shipmounted retractableking post fitted with a swinging arm designed to carry one end of acable of a high-line load transfer system,

FIG. 2 represents an elevation of the kingpost in its retractedposition,"

FIGS. 3 and 4 represent plan sections along the. lines III III and IV IVof FIG. 1 I FIG. 5 represents a plan view of the kingpost in its raisedposition,

FIG. 6 represents the hydraulic system employed for raising and loweringthe kingpost and swinging arm in diagrammatic form, and

' FIG. 7 shows a modified form of swinging arm.

Thus referring to the drawings the kingpost 1 comprises a pair of broadflanged, essentially vertical beams 2 joined together at the top end bya saddle piece 3 integral with a top trunnion 4.'On this trunnion 4 aboss and lug assembly 5 is provided to enable two tubular steelbackstays 6 to be pivotally attached to the trunnion, a hatch cover 30being rigidly secured to the asv sembly above'the trunnion 4.

14 to one end of the arm 7 so that the other end of the V arm can beraised or lowered under the control of the piston, the latter end of thearm being terminated by eyes to which the jackstay of a high-loadtransfer system can beattached. The lower end of the cylinder 13 isprovided with a further piston 15 in the form of a ram 16 carrying apulley 17 at its outer extremity as shown. The cylinder barrel isprovided at both ends with a normal gland assembly, and in addition isfitted at its lower end with a square section structural steel extension18 at the bottom of which the unit is pivoted on a bracket 19 attachedto the verticalbeams 2. A wire rope 20 is connected to a bracket 21fixed to the lower end of the cylinder 13, the rope passing around thepulley 17, and around further pulleys 22 mounted on the structuralextension, and being connected at its opposite end to a bracket 23 fixedto the underside of a platform 24a carried by a slewing ring 24. Theslewing ring is carried by brackets 25 fixed within a short tubular duct26 which is fitted into an opening in the deck 27, the slewing ringbeing just below deck level as shown.

The piston 12 controlling the pivoting of the swinging arm 7 is attheupper extremity of its travel when the arm is in its inoperativeorstowed position lying parallel to the beams 2 as shown in FIG. 2. Whenthe kingpost is in the retracted position the head of the ram 16 isclose to the upper piston 12, and the complete assembly is supportedfrom the hatch cover 30 which rests on the top edge of the duct 26 asshown in FIG. 2, the bottom ends of the beams being secured againsttransverse movement by a location bracket 31.

A tubular trunkway 32 accommodates the assembly when the latter is inthe retracted position.

At the start of an operation hydraulic fluid is admitted to the bottomof the cylinder 13, and the ram 16 is forced downwards out of thecylinder. This has the effect of raising the kingpost assembly out ofthe trunkway, the hatch cover 30 being lifted with it.

When the assembly reaches the fully raised position, spring loadedlatches 29 within the duct automatically engage so as to lock andsupport the assembly in the raised position; at the same time a limitswitch is operated to arrest the motor M driving the reversible constantpressure hydraulic pump P feeding hydraulic fluid into the cylinder 13,and suitable means 35 is operated to release the mechanical latch 36securing the swinging arm 7' in the stowed position to permit the arm tobe raised.-

Raising of the swinging arm 7 is effected by reversing the electricmotor M to cause the pump P to supply hydraulic fluid to the end of thecylinder 13, thus forcing the piston 12 downwards and raising theoperative end of the arm, openings'33 (FIG. 6) in the head 34 of th rampermitting the hydraulic fluid within the cylinder 13 to be recirculatedback to the pump P.

The upper end of the assembly is stabilised against transverse movementby the attachment of the lower end of the backstays 6 to suitablypositioned deck cleats 35.

Returning the assembly to its stowed position involves the abovesequence in reverse, the latches being retracted by a hand-operatedlever (not shown).

The slewing ring enables the whole kingpost assembly to be rotated abouta nominally vertical axis to allow for port or starboard rigging, deckcleats being provided in appropriate positions for the backstays. Inaddition with the backstays fixed to the deck cleats the vertical beams2, arm 7 and actuating cylinder 13 can be rotated within limits to allowfor a t30 station keeping error. To the underside of the supportplatform carried by the slewing ring there are attached brackets 41 andguide rollers 42 which locate and support the assembly as it is beingraised out of the trunkway before the backstays have been secured totheir respective deck cleats.

It will be noted that the cylinder unit 13 passes through the slewingring support platform and is free to tilt as a result of the movement ofthe swinging arm.

The lower end of the vertical beams 2 are arranged to act as thebedplate for the main hydraulic drive components, namely the motor Mwith an electro magnetic brake, the pump P as well as hydraulic boostaccumulators A, make-up pump MP and tank unit T.

The hydraulic system is shown in diagrammatic form in FIG. 6.

The emergency hand drive E is provided by a hand pump HP together with adirectional control'valve DV across the cylinder feed ports.

Electrical connections between the kingpost unit and the trunkway are inthe form of a multicore cable loop and control is by pendant normallystored beneath. an access cover (not shown) adjacent the unit. Thus uponremoval of the cover the pendant can be lifted out unwinding a trailingcable which is stored on a spring loaded cable reeling drum (also notshown) attached to a suitable mounting bracket.

A power source, which may be an electrically or hydraulically poweredmotor, may be provided for effecting the rotation of the slewing ring24. Such a motor may, for example, be mounted outside the tubular duct26, and be coupled to the ring by gearing, a chain drive or othersuitable form of coupling means.

In place of the power pack provided by the motor M and pump P forraising and lowering the kingpost assembly and swinging arm 7 aring-main hydraulic drive system may be employed, connections from thehydraulic drive system to cylinder 13 being made through suitablecouplings and flexible pipes, to allow for the movement of the cylinderin use, of the assembly.

In some cases it may be desirable for the deck to be clear ofobstructions when the kingpost assembly is in the retracted position,and in such a case the coaming at the top of the duct 26 may be recessedbelow the level of the deck so that when the assembly is lowered theupper surface of the hatch cover 30 lies flush with the deck. The deckcleats 35 can also be located in recesses and covered by openable orremovable plates lying flush with the deck when not in use.

In an alternative arrangement (FIG. 7) the end of the swinging arm canbe constructed as described in United Kingdom Patent Specification No.1226440 so that during load lowering the effective high point istransferred from the arm attachment point to a point approximately inline with the centre line of the traveller block. Thus the lever armrepresented by the distance between these two points is eliminated asthe arm comes down and the element of judgement on the part of theoperator, otherwise necessary in rough weather conditions, to bringabout an impact free landing on the deck of the ship, is no longerrequired.

We claim:

1. A retractable post assembly for carrying an end of a load-supportingcable comprising:

a post,

a carrier member consisting of a swinging arm pivoted to the post abouta nominally horizontal axis having an inoperative position in which itextends downwards substantially parallel to the post to permit the postto be retracted,

means for raising or retracting the post,

a fluid operated piston and cylinder unit having a pair of pistonsselectively operable one at each end of the cylinder which is pivoted tothe post,

one of which pistons controls said post raising or retracting means, and

the other of which pistons is arranged to raise the arm from aninoperative position to an operative position when the post has beenraised from retracted position,

latching means for latching the arm in its inoperative position,

further latching means for latching the post in its raised position, and

means for feeding fluid into the piston and cylinder unitwith theswinging arm latched in its inoperative position, to cause the piston atsaid one end of the piston and cylinder unit to extend and raise thepost, and for subsequently feeding fluid into the opposite end of thepiston and cylinder unit with the post latched in the raised positionand the swinging arm released, to cause the other piston to retract andthereby raise the arm.

2. A retractable post assembly accordingto claim 1 wherein the pistonthat controls the raising and lowering of the post is located at thelower end of the cylinder, and is in the form of a ram carrying apulley, a cable having' one end connected to the post assembly and theother end connected to a support member, passing around the pulley toprovide a support for the assembly so that as the ram is extendedtheassembly is raised.

3. A retractable post assembly according to claim 2 wherein the cablepasses around a plurality of other pulleys carried by the assembly inorder to magnify the movement of the assembly for a given movement ofthe ram, thus enabling the relatively large movement of the assembly tobe obtained for a relatively small movement of the ram.

4. A retractable post assembly according to claim 2 wherein the supportis provided by a slewing ring through which the post assembly extends topermit the whole assembly to be rotated about 'a nominally verticalaxis.

5. A retractable post assembly according to claim 4 including a powersource for effecting the rotation of the slewing ring.

6. A retractable post assembly according to claim 1 wherein the raisingand lowering of the post and the movement of the arm are controlled by ahydraulic system, the various parts of the system being carried by thepost so that the whole of the post assembly can be removed or replacedas a complete unit.

7. A retractable post assembly according to claim 1 incorporating ahydraulic system for raising and lowering the post and for controllingthemovement of the arm, said hydraulic system comprising a reversibleconstant pressure hydraulic pump arranged to feed hydraulic fluid intothe cylinder of the piston and cylinder unit, a reversible electricmotor for driving the pump, the motor being energizable to drive thepump in one direction to raise the post with the swinging arm latched inthe direction to raise the post with the swinging arm latched in theinoperative position, means for automatically locking the post in theraised position, and for operating a limit switch to dc-energize themotor when the post reaches the fully raised position.

8. A retractable post assembly according to claim 7 including also meansfor automatically releasing the latch securing the swinging arm in theinoperative position when the post reaches the fully raised position,the motor being energizable in the reverse direction to raise the arm toits operative position.

9. A retractable post assembly according to claim 1 wherein the post issubstantially completely retractable below a hatch in a deck, platformor the like and supports at its upper end a hatch cover, so that in theretracted condition the cover closes the hatch opening through which theassembly can be raised.

10. A retractable post assembly according to claim 9 wherein the hatchopening is recessed below the level of the deck, platform or the like sothat in the retracted position theupper surface of the cover issubstantially flush with the surface of the deck,.platform or the like.

the'pistonand cylinder unit to the system.

1. A retractable post assembly for carrying an end of a loadsupportingcable comprising: a post, a carrier member consisting of a swinging armpivoted to the post about a nominally horizontal axis having aninoperative position in which it extends downwards substantiallyparallel to the post to permit the post to be retracted, means forraising or retracting the post, a fluid operated piston and cylinderunit having a pair of pistons selectively operable one at each end ofthe cylinder which is pivoted to the post, one of which pistons controlssaid post raising or retracting means, and the other of which pistons isarranged to raise the arm from an inoperative position to an operativeposition when the post has been raised from retracted position, latchingmeans for latching the arm in its inoperative position, further latchingmeans for latching the post in its raised position, and means forfeeding fluid into the piston and cylinder unit with the swinging armlatched in its inoperative position, to cause the piston at said one endof the piston and cylinder unit to extend and raise the post, and forsubsequently feeding fluid into the opposite end of the piston andcylinder unit with the post latched in the raised position and theswinging arm released, to cause the other piston to retract and therebyrAise the arm.
 2. A retractable post assembly according to claim 1wherein the piston that controls the raising and lowering of the post islocated at the lower end of the cylinder, and is in the form of a ramcarrying a pulley, a cable having one end connected to the post assemblyand the other end connected to a support member, passing around thepulley to provide a support for the assembly so that as the ram isextended the assembly is raised.
 3. A retractable post assemblyaccording to claim 2 wherein the cable passes around a plurality ofother pulleys carried by the assembly in order to magnify the movementof the assembly for a given movement of the ram, thus enabling therelatively large movement of the assembly to be obtained for arelatively small movement of the ram.
 4. A retractable post assemblyaccording to claim 2 wherein the support is provided by a slewing ringthrough which the post assembly extends to permit the whole assembly tobe rotated about a nominally vertical axis.
 5. A retractable postassembly according to claim 4 including a power source for effecting therotation of the slewing ring.
 6. A retractable post assembly accordingto claim 1 wherein the raising and lowering of the post and the movementof the arm are controlled by a hydraulic system, the various parts ofthe system being carried by the post so that the whole of the postassembly can be removed or replaced as a complete unit.
 7. A retractablepost assembly according to claim 1 incorporating a hydraulic system forraising and lowering the post and for controlling the movement of thearm, said hydraulic system comprising a reversible constant pressurehydraulic pump arranged to feed hydraulic fluid into the cylinder of thepiston and cylinder unit, a reversible electric motor for driving thepump, the motor being energizable to drive the pump in one direction toraise the post with the swinging arm latched in the direction to raisethe post with the swinging arm latched in the inoperative position,means for automatically locking the post in the raised position, and foroperating a limit switch to de-energize the motor when the post reachesthe fully raised position.
 8. A retractable post assembly according toclaim 7 including also means for automatically releasing the latchsecuring the swinging arm in the inoperative position when the postreaches the fully raised position, the motor being energizable in thereverse direction to raise the arm to its operative position.
 9. Aretractable post assembly according to claim 1 wherein the post issubstantially completely retractable below a hatch in a deck, platformor the like and supports at its upper end a hatch cover, so that in theretracted condition the cover closes the hatch opening through which theassembly can be raised.
 10. A retractable post assembly according toclaim 9 wherein the hatch opening is recessed below the level of thedeck, platform or the like so that in the retracted position the uppersurface of the cover is substantially flush with the surface of thedeck, platform or the like.
 11. A retractable post assembly according toclaim 1 wherein the raising and lowering of the post and the movement ofthe arm are controlled by an external hydraulic system, and means areprovided for connecting the piston and cylinder unit to the system.